(i) Field of the Invention
The present invention relates to 3-azabicyclo-[3.1.0]hexane-2-one derivatives and herbicidal compositions containing them as herbicidally active ingredients.
(ii) Description of the Prior Art
In U.S. Pat. No. 3,745,170, it is described that certain kinds of 3-azabicyclo[3.1.0]hexane derivatives show a sterilizing activity. A typical compound mentioned in this publication, 1,5-dimethyl-3-(3,5-dichlorophenyl)-3-azabicyclo[3.1.0]hexane-2,4-dione (general name: procymidone) is commercially available as a gray mold disease inhibitor. Furthermore, in Journal of Chromatography, Vol. 318(2), pp. 398-403 (1985), there is mentioned 3-ethyl-1-phenyl-3-azabicyclo[3.1.0]hexane-2-one, but reports regarding a herbicidal activity are not present. In addition, U.S. Pat. Nos. 4,118,393 and 4,196,120 disclose 3-benzyl-1-phenyl-3-azabicyclo[3.1.0]hexane-2,4-dione derivatives as an antidepressant and its synthetic intermediate, but reports regarding the herbicidal activity are not present.
In recent years, a herbicidal composition having a high selectivity is strongly desired which has no injurious action on crops and which can exterminate weeds alone. Furthermore, for paddy fields, an effective herbicidal composition is desired which can securely control hardly eliminable weeds such as barnyardgrass (Echinochloa), bulrush (Scirpus juncoides), monochroria (Monochoria vaginalis) and water nutgrass (Cyperus serotinus). In addition, it is strongly required to develop a herbicidal composition which is usable in an optional term of from the pre-emergence of weeds to the growing period of the emerged weeds and which maintains the herbicidal effect for a long period of time.
In consequence, the present invention intends to provide a selective herbicidal composition which has no injurious action on rice plants in paddy fields, has a wide herbicidal spectrum in a low application rate, and can be used in a prolonged term of from the pre-emergence of weeds to the growing period of the emerged weeds.